1. Field of the Invention
In the art of cleaning compositions for use in cleaning hard surfaces, particularly the art of cleaning tableware and other food-soiled utensils in machine dishwashers, the problem of spotting, filming and defoaming of the machine washload is present. Liquid detergent compositions were introduced to the market and offered ease and convenience of handling. Since their introduction, such detergent compositions have captured upwards of 30 percent of the home market. However, these liquid detergent compositions have suffered certain deficiencies relative to powdered machine dishwashing detergents. Specifically, although they offer ease of manufacture and handling, they have inferior spotting, filming and defoaming characteristics relative to the powdered compositions.
It is believed that these deficiencies are the result of the fact that most detergent compositions contain a chlorine bleach component, such as hypochlorite bleach, and these chlorinating agents degrade conventional defoaming nonionic surfactants such as ethylene oxide/propylene oxide block copolymers and fatty alcohol, fatty acid, fatty amide and alkyl phenol oxyalkylates. As the chlorinating agent attacks the nonionic surfactant, the bleach is depleted and the surfactant is destroyed. Thus, spotting, defoaming and filming properties are lost along with the properties of the chlorinating agent.
In the past, liquid automatic dishwashing detergent compositions have been formulated with anionic surfactants such as alkyl diphenyloxide disulfonates, or with no surfactants present at all. The use of anionic surfactants or no surfactants in liquid automatic dishwashing detergent compositions contributes greatly to the spotting, filming and defoaming problems associated with such liquid compositions. Thus, there is a greatly felt need in the industry to formulate a liquid, automatic dishwashing detergent composition which contains nonionic surfactants and which do not break down under attack from chlorinating agents which may be present in the composition.
The present invention relates to the use of sterically hindered epoxide-capped polyether polyols as nonionic surfactants in cleaning formulations which include alkaline hypochlorite bleaching agents. The use of such polyols allows such formulations to retain their cleaning and defoaming properties for longer periods than formulations containing conventional nonionic polyether surfactants.
2. Description of the Related Art
Mori et al, U.S. Pat. No. 4,703,114, disclose polyethers having tertiary alcoholic terminals. The polyethers are of the formula: ##STR1## wherein:
R is the residue of a starting active hydrogen compound with removal of the active hydrogen atom, R.sub.1 is a C.sub.1 -C.sub.10 alkyl or aryl, R.sub.2 is a C.sub.1 -C.sub.10 alkyl, R.sub.3 is H, CH.sub.3, C.sub.2 H.sub.5 or phenyl, x is 5 to 100, y is 1 to 5, and z is 1 to 8.
These polyethers are less active than those having primary or secondary alcoholic functions at their terminal ends. These hydroxyl terminated polyethers find use as raw materials for polyurethane and polyester resins and are suggested for use in cosmetics, plasticizers, surfactants and raw materials for these products.
In the preparation of the polyethers, the starting active hydrogen compounds include monohydroxyl compounds or polyhydroxyl compounds such as propylene glycol. About 5 to 100 moles per active hydrogen atom of alkylene oxide and/or styrene oxide may be reacted with the starting active hydrogen compound to give polyethers. When these polyethers contain different recurring units, these units may form either random or block copolymers. The polyethers can be reacted with 1 to 5 moles per hydroxyl group of an epoxide. Preferred epoxides include isobutylene oxide.
There is no showing in Mori et al that these materials exhibit unexpected stability in the presence of chlorine bleach while retaining spotting, defoaming and filming properties in liquid detergent compositions which are comparable with powdered detergents.
Horsley et al, U.S. Pat. No. 2,886,600, relate to the production of isobutyl ethers of hydroxy compounds, and particularly to the production of isobutyl ethers of glycol and polyglycol monoethers.
There is no showing that these compounds make excellent nonionic surfactants which exhibit surprising stability in detergent compositions containing chlorine bleach.
None of the art, insofar as is known, describe the use of nonionic polyether polyols which are capped with sterically hindered epoxides, in liquid detergent compositions containing chlorine bleach. It is an advance in the art to include nonionic surfactants into liquid detergent compositions containing chlorine bleach and retain adequate storage stability.